//导航
.nav 
    margin: 50px
    ul 
        list-style: none
        li  
            float left
            span 
                width: 60px
                a
                    padding-right: 50px
//正文
.box
    text-align: center
    .logo 
         margin: 0 auto
         width: 150px
        img
           width: 150px
    form
        p 
            input[type="text"]
                width: 250px
                margin-bottom: 15px
            input[type="submit"]      
                border-radius: 10px      